Abrasive device



Aug. 16, 1966 BL 3,266,200

' ABRASIVE DEVICE Filed June 4, 1964 an [I 14/ 5 United States Patent fornia Filed .Iune 4, 1964, Ser. No. 372,609 5 Claims. (Cl. 51377) This invention relates to a power-driven abrasive device and, more particularly, relates to such a device in which a flexible abrasive disk member is replaceably mounted on a rotary drive member.

The abrasive disk member is commonly of laminar construction comprising a front layer of fabric coated with abrasive particles and a backing layer. Since abrasive disk members have short service lives they must be replaced frequently and for the sake of economy it is essential not only that such a disk member be of simple inexpensive construction but also that the task of replacing the disk member be a simple and convenient operation that may be carried out quickly.

Cooperating means on the disk member and the rotary drive member, respectively, must be provided for releasable interlocking engagement and the interlocking engagement must accomplish two functions. One function is to prevent axial separation of the disk member from the rotary drive member. The other necessary function is to releasably engage the disk member with the rotary drive member in a manner to cause the abrasive disk member to be driven without rotary slippage.

The embodiment of the invention disclosed herein provides a first pair of cooperative means in the disk member and the drive member respectively to prevent axial separation of the two members. One of this pair of cooperative means is in the form of a knob or boss with a reduced neck on one of the two members and the other of the second pair of cooperative means is a plurality of resilient elements on the other of the two members to yieldingly embrace the boss in engagement with the neck of the boss.

The invention further provides a second pair of cooperative means on the disk member and the drive member respectively to drive the disk member without rotary slippage. One of this second pair of cooperative means comprises ho'ok elements on the disk member and the other of the second pair of cooperative means comprises corresponding radially outward elements on the drive member that are releasably engageable by the hook elements.

With such a construction it is a simple matter either to mount a new abrasive disk on the drive member or to remove a worn abrasive disk from the drive member. To mount a new abrasive disk on the drive member, it is merely necessary to position the abrasive disk concentrically of the drive member and then to press the disk against the drive member to force the cooperative resilient elements of one of the two members over the boss of the other member into releasable engagement with the neck of the boss. The abrasive disk member may then be rotated relative to the drive member to bring the hook elements of the disk member into engagement with the corresponding radial elements on the rotary drive member for the dual purpose of locking the two members against separation and of preventing relative rotation between the two members.

The features and advantages of the invention may be understood from the following detailed description and the accompanying drawing.

FIG. 1 is a sectional view of the selected embodiment of the invention showing a disk member mounted on a drive member;

FIG. 2 is a perspective view from below of the disk member of FIG. 1; and

ice

FIG. 3 is a perspective view from above of the drive member of FIG. 1.

As shown in FIG. 1, an abrasive disk member, generally designated 10, has an outer layer 12 of fabric coated with abrasive particles and has an inner backing layer 14 of suitable material such as fiberboard that is bonded to the fabric in a unitary manner by suitable adhesive. The abrasive disk 10 is adapted to be removably mounted on a drive member, generally designated 22, in the form of a cylinder having longitudiniai end slits to form a circumferential series of inwardly bent resilient fingers 24 and a second series of alternate outwardly bent resilient fingers 2'5. Mounted on the underside of the abrasive disk 10 is a molded plastic member 26 which forms a boss 28 having a neck portion 30 which forms a circumferential shoulder surface 32. The plastic member may be made of nylon, for example, and the boss 28 may be hollow if desired to give the boss a degree of resiliency. The plasticmember 26 is formed with a radial flange 31 around the boss 28 and a plurality of circumferentially spaced hook elements 36 are mounted on the radial flange for engagement with the inwardly bent ends of the flexible fingers 24 of the drive member.

To mount the abrasive disk 10 on the drive member 22 the disk is oriented with the hook elements 35 in aligniment with gaps formed by the inwardly bent resilient fingers 2 4 of the drive member. The abrasive disk is then pressed against the drive member to force the boss 28 past the inwardly turned flexible fingers 24 thereby to cause the inwardly turned flexible fingers to embrace the neck 30 of the boss 28. The abrasive disk 10 is then rotated relative to the drive member 22 to cause the hook elements 35 to engage the inwardly bent flexible fingers 2 4.

It is to be noted that the hook elements 35 may be positioned and adapted for engagement with the outwardly bent fingers 25 instead of the inwardly bent fingers 24. In either event the hook elements engage with what may be termed radially outward elements.

The hook elements 35 point in one circumferential direction but the driving rotation of the drive member 22 is in the opposite circumferential direction. If an operator forces the abrasive disk into frictional engagement with the drive member without manually rotating the abrasive disk to bring the hook elements into engagement with the radially outward elements the initial driving rotation of the operating member will cause the hook elements of the disk to engage the drive member because the inertia of the disk will hold it back to cause the required relative movement between the disk and the drive member. In the event that the inertia of the disk is not sufficient to cause positive engagement of the hook elements with the drive member the application of the rotating disk to a workpiece will accomplish the same result because the workpiece will act as a brake on the disk. When the operating member is decelera ted there may be a tendency for the hook elements to become disengaged from the drive member but in that event subsequent resumption of operation will cause the hook elements to become engaged. It is apparent that the resilient grip of the inwardly turned fingers 24 on the neck 30 of the boss 28 serves the purpose of normally preventing axial separation of the disk from the drive member thereby to permit the hook elements to engage and disengage in the manner described.

My description in specific detail of the selected embodiment of the invention will suggest various changes, substitutions and other departures from my dis-closure within the spirit and scope of the appended claims.

I claim:

1. In an apparatus of the character described, means for mounting an abrasive disk member on a rotary drive member, comprising:

a boss on one of said two members formed with a neck of reduced diameter;

resilient elements on the other of said two members to yieldingly embrace the neck of the boss to yieldingly retain the disk member on the boss;

hook elements on the disk separate from the resilient elements positioned radially outward from the center of the disk and pointing in one circumferential direction; and

radially outward elements on the drive member for hook engagement by said hook elements to positively prevent axial separation of the two members and to interlock the two members for rotation in the opposite circumferential direction, said hook elements engaging the radially outward elements in response to rotation of the disk member in said opposite circumferential direction when said resilient elements embrace the neck of the boss.

2. A combination as set forth in claim 1 in which the boss and hook elements are on the disk and the resilient elements together with the radial elements are on the drive member.

3. In an apparatus of the character described, means for mounting an abrasive disk member on a rotary drive member, comprising;

a circumferential series of longitudinal fingers with radiially inwardly turned end portions on the rotary drive member, the fingers defining an axial cavity with the inwardly turned end portions of the fingers overhanging the interior of the cavity;

a concentric boss on the disk member dimensioned for insertion into said cavity, the boss having a reduced neck portion for engagement by the inwardly turned ends of the fingers; and

hook elements on the disk member positioned for engagement with the inwardly turned ends of the fingers in response to rotation of the disk member relative to the drive member when the disk is mounted on the drive member with the fingers of the drive member embracing the neck portion of the boss.

4. A combination as set forth in claim 3 in which said boss is made of resilient plastic material.

5. In an apparatus of the character described, means for mounting an abrasive disk member on a rotary drive member, comprising:

hook elements on the disk member spaced radially outwardly from the boss for engagement with the bent ends of one of the two sets of fingers.

References Cited by the Examiner UNITED STATES PATENTS 3,157,010 11/1964 Block 51377 ROBERT C. RIORDON, Primary Examiner.

LEONARD S. SELMAN, Examiner. 

1. IN AN APPARATUS OF THE CHARACTER DESCRIBED, MEANS FOR MOUNTING AN ABRASIVE DISK MEMBER ON A ROTARY DRIVE MEMBER, COMPRISING: A BOSS ON ONE OF SAID TWO MEMBERS FORMED WITH A NECK OF REDUCED DIAMETER; RESILIENT ELEMENTS ON THE OTHER OF SAID TWO MEMBERS TO YIELDINGLY EMBRACE THE NECK OF THE BOSS TO YIELDINGLY RETAIN THE DISK MEMBER ON THE BOSS; HOOK ELEMENTS ON THE DISK SEPARATE FROM THE RESILIENT ELEMENTS POSITIONED RADIALLY OUTWARD FROM THE CENTER OF THE DISK AND POINTING IN ONE CIRCUMFERENTIAL DIRECTION; AND RADIALLY OUTWARD ELEMENTS ON THE DRIVE MEMBER FOR HOOK ENGAGEMENT BY SAID HOOK ELEMENTS TO POSITIVELY PREVENT AXIAL SEPARATION OF THE TWO MEMBERS AND TO INTERLOCK THE TWO MEMBERS FOR ROTATION IN THE OPPOSITE CIRCUMFERENTIAL DIRECTION, SAID HOOK ELEMENTS ENGAGING THE RADIALLY OUTWARD ELEMENTS IN RESPONSE TO ROTATION OF THE DISK MEMBER IN SAID OPPOSITE CIRCUMFERENTIAL DIRECTION WHEN SAID RESILIENT ELEMENTS EMBRACE THE NECK OF THE BOSS. 